Why did environmental ethics expand moral consideration beyond humans?

"This development came with the awareness that humans may not be the only morally worthy beings, hence the need to develop moral theories that could account for ecosystems, the environment, and other beings. Such a way of thinking may very well be ‘stating the obvious’ nowadays, but for a long time—at least in Western philosophy—little consideration had been given to other beings from a moral perspective. Caring for other-than-human animals and protecting them may seem intuitively right, and many have stood up against organizations and individuals like poachers who threaten them, but that has not always been the case."